In Sindarin, plurals are formed in a decided
pattern (with the exception of a few words, listed near the bottom of this
page). Once the system is learned, any noun can be pluralized without
concern. This system involves not suffixes, but a change in vowels.
Ex: "adan" has a plural of "edain".

*****

a:

(in monosyllables) a or á > â

(in monosyllables) â > ai

(in final syllables) a > ai

(in non-final syllables) a > e

(in non-final syllables) á > é

***

e:

(in mono and final syllables) e > i

(in mono and final syllables) é > í

(in mono and final syllables) ê > î

(in non-final
syllables) no change

***

i:

does not change

***

o:

(in mono and final syllables) o > y

(in mono and final syllables) ó or ô > ý

(in mono and final syllables) io > y

(in non-final syllables) o > e

***

u:

u > y

ú > ý

û > ui

in a small group of words, u does not change but it does force a to become
ei:

anu "male animal" - einu

inu "female animal" - inu

celu "water spring" - cilu

galu "blessing"- geilu

gwanu "death" - gweinu

haru "wound" - heiru

hithu "fog" - hithu

nedhu "cushion" - nidhu

neun - niun

pathu "level space" - peithu

tinu "spark, small star" - tinu

tindu "starry night" - tindu

***

y:

does not change

**

au:

(in some older words) au > ui

(the rest of the time) au > oe

**

ai:

usually does not change

in a small group of words, ai does change; these words are

cai "fence" - cî

cair "ship" - cîr

fair (feir) "mortal being" - fîr

fair "right hand" - fýr

gwain "new" - gwîn

sain (sein) "new" - sîn

lhain "thin, lean, meager" - lhîn

paich "juice, syrup" - pich

***

ie:

ie > i

ae, ea, ei, ui:

do not change

**

special cases where plurals are irregular

êl "star" - elen

Elda "Elf" - Eldar (actually this is not so much
an irregular plural as a Quenya-based one)

This is a particular way of forming double and singular nouns.Most likely a remnant of the Silvan tongue, this method involves certain
words which are "singular" when speaking of a pair of objects that
belong together.To speak of one of
a pair, the suffix -ig is added.Few
of these words remain, and even these were more common in the slightly older
forms of Sindarin.By the late
Third Age this formation was mostly extinct in "modern" Sindarin,
instead replaced by using the former dual-form as a singular, and forming
plurals in the regular method.However,
as such words may still be found in older writings, it is worth mentioning.